How severe is CVE-2023-25563?

CVE-2023-25563 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-25563 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-25563?

CVE-2023-25563 affects Gss-ntlmssp Project Gss-ntlmssp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-25563?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-25563 published?

CVE-2023-25563 was published on 2023-02-14 and last updated on 2026-06-17.

CVE-2023-25563

CVE-2023-25563 is a medium-severity vulnerability in Gss-ntlmssp Project Gss-ntlmssp with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Gss-ntlmssp Project Gss-ntlmssp
Published: 2023-02-14
Last modified: 2026-06-17

Description

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, multiple out-of-bounds reads when decoding NTLM fields can trigger a denial of service. A 32-bit integer overflow condition can lead to incorrect checks of consistency of length of internal buffers. Although most applications will error out before accepting a singe input buffer of 4GB in length this could theoretically happen. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point if the application allows tokens greater than 4GB in length. This can lead to a large, up to 65KB, out-of-bounds read which could cause a denial-of-service if it reads from unmapped memory. Version 1.2.0 contains a patch for the out-of-bounds reads.

Frequently asked questions

What is CVE-2023-25563?: GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, multiple out-of-bounds reads when decoding NTLM fields can trigger a denial of service. A 32-bit integer overflow condition can lead to incorrect checks of consistency of length of internal buffers. Although most applications will error out before accepting a singe input buffer of 4GB in length this could theoretically happen. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point if the application allows tokens greater than 4GB in length. This can lead to a large, up to 65KB, out-of-bounds read which could cause a denial-of-service if it reads from unmapped memory. Version 1.2.0 contains a patch for the out-of-bounds reads.
How severe is CVE-2023-25563?: CVE-2023-25563 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-25563 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-25563?: CVE-2023-25563 affects Gss-ntlmssp Project Gss-ntlmssp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-25563?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-25563 published?: CVE-2023-25563 was published on 2023-02-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gss-ntlmssp_project:gss-ntlmssp:*:*:*:*:*:*:*:*

More vulnerabilities in Gss-ntlmssp Project Gss-ntlmssp

CVE-2023-25567 — High (CVSS 7.5): GSS-NTLMSSP, a mechglue plugin for the GSSAPI library that implements NTLM authentication, has an out-of-bounds read…
CVE-2023-25566 — High (CVSS 7.5): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, a…
CVE-2023-25565 — High (CVSS 7.5): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, an…
CVE-2023-25564 — Medium (CVSS 6.5): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0,…

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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